The present invention pertains to a folding device for carton bottoms. More particularly, this invention pertains to an apparatus for in-folding and sealing over-folded carton bottoms.
A common form of container for milk, juice and the like is the gable top carton. In this regard, packaging technology has made enormous strides vis-à-vis these gable top cartons, as well as other types of packages. Present technology permits the packaging of perishable food items for non-refrigerated shelf lives that can be as much as 90 days. Such packages provide the ability to bring these food items into parts of the world that have limited transportation, distribution and storage infrastructure.
In an effort to continue to expand on the ability to extend the shelf life of perishable food items, various carton or package configurations have come into use. Some of these packaging configurations include extended shelf life (xe2x80x9cESLxe2x80x9d) packaging and aseptic packaging. Another known packaging configuration is the high acid ambient distribution (xe2x80x9cHAADxe2x80x9d) package, which also provides an enhanced shelf life. The HAAD package is configured for packaging materials, such as foodstuffs, that are relatively acidic (e.g., pH less than about 4.6), such as citrus juices.
In addition to the ever increasing shelf life demands for these perishable food items, the processing and packaging of the food items must also be carried out in a cost effective and efficient manner so that the packaged food items remain within the grasp of the purchasing public. To this end, the demands on packaging machines have become greater, in particular, relative to operating speeds. One type of packaging machine is referred to as a xe2x80x9cform, fill and sealxe2x80x9d machine, in which cartons or packages are constructed, filled and sealed in a sterile environment by a single machine. The operating speeds of some of these machines exceeds 10,000 packages per hour.
In order to maintain the integrity of the package after it is filled and sealed, advanced technologies have been applied to the carton materials, as well as the processing operations. Many such packaging materials are formed from paperboard or fiberboard-based materials formed in a composite structure. Typically, one or more layers, such as polymeric coatings, foil coatings and the like, are applied to the paperboard or fiberboard substrate to reduce or eliminate the gas and liquid permeability of the substrate material, and to accommodate relatively acidic contents, such as citrus based products.
When forming the carton or package, large stock material is typically cut into xe2x80x9cblanksxe2x80x9d that are used to form the carton. The stock material is folded or scored to a particular pattern, and the blank is folded along these score lines to form the carton. The various edges of the material are sealed or joined to one another to form the constructed carton. It has however, been observed that the edges of the material, where the material has been cut through the composite structure, can be susceptible to wicking of liquids from outside of the carton.
To this end a variety of carton bottom configurations have been used to overcome this wicking problem as well as other storage and/or distribution problems. One such bottom configuration is referred to as an over-folded bottom configuration. In this configuration, the carton bottom is formed from a plurality of panels, at least some of which are folded over themselves and other panels and are sealed to one another to form the sealed carton bottom.
Accordingly, there exists a need for a carton bottom folding device for folding and sealing over-folded carton bottoms, which device can be used with known form, fill and seal machines. Desirably, such a folding device can accommodate carton folding operations at the operating speeds of known filling machines. Most desirably, the folding device provides a tight, high-confidence bottom seal for paperboard and fiberboard based cartons for the storage of food items and the like.
A bottom forming apparatus is adapted for use in a packaging machine to form and seal a bottom of a carton of a series of cartons being processed on the packaging machine. The cartons each including a plurality of carton bottom panels configured for infolding and sealing to form the sealed carton bottom.
The bottom forming apparatus includes a mandrel turret having a plurality of mandrels projecting outwardly therefrom. The mandrel turret rotates about a fixed axis. A sealing station is disposed at a fixed position relative to the rotation of the mandrel turret. The sealing station receives each of the mandrels having a carton thereon. The sealing station includes a guide plate and first and second rotatable spindles. The spindles each have a pre-folding member and a final folding member extending therefrom.
A carton is advanced to the sealing station with the plurality of bottom panels substantially unfolded. As the spindles rotate, the pre-folding members and final folding members engage the plurality of carton bottom panels and fold the bottom panels inwardly to urge the panels into a folded condition. In a preferred embodiment, the guide plate is disposed to engage the bottom of a carton subsequent to folding by the final folding members to further urge the panels into the folded condition.
In a current embodiment, the pre-folding members are elongated rods projecting from their respective spindles and the final folding members are elongated rods projecting from their respective spindles, each at a predetermined angle relative to its respective pre-folding member. Preferably, the final folding members are formed having arcuate surfaces that engage the carton bottom panels.
The guide plate can be formed having an angled portion and a substantially flat portion, with the angled portion being proximal to the carton coming into engagement therewith.
To provide a seal for the carton bottom, a sealing plate is disposed subsequent to the guide plate and a mandrel plate is disposed on each of the mandrels. The plurality of folded carton bottom panels are compressed between the sealing plate and the mandrel plate to effect the carton bottom panel seal. The apparatus can include a heating station disposed prior to the sealing station relative to the rotation of the mandrel turret. The apparatus can also include a discharge station disposed subsequent to the sealing station for discharging the bottom sealed cartons, and an infeed station disposed prior to the heating station relative to the rotation of the mandrel turret for feeding the cartons onto the mandrels of the mandrel turret.
In a preferred embodiment, each mandrel plate has a plurality of flat surface areas and a plurality of recess areas, and the sealing plate has a plurality of projecting areas that correspond to the recess areas of the mandrel plates. The sealing plate engages each of the mandrel plates, with the folded bottom panels therebetween, during forming of the bottom of the carton.
A packaging machine for forming, filling and sealing a series of cartons includes a mandrel turret and a bottom forming station for forming the sealed carton bottoms. The packaging machine further includes a filling station disposed subsequent to the bottom forming station and a top sealing station disposed subsequent to the filling station. The packaging machine can further include a sterilization station disposed prior to the filling station. The packaging machine can be configured to produce a high acid ambient distribution product.
A method for forming a sealed bottom of a carton on a packaging machine includes the steps of placing an erected carton on a mandrel of a mandrel turret that rotates about a fixed axis. The carton has a plurality of substantially unfolded carton bottom panels that are pre-folded at a sealing station to form a plurality of pre-folded bottom panels. The pre-folded bottom panels are final folded after the pre-folding step, at the sealing station, to form a plurality of final folded carton bottom panels. The final folded carton bottom panels are guided to a sealing plate at the sealing station and are sealed to form the sealed carton bottom.
The method can include the step of heating the bottom panels at a heating station prior to the step of pre-folding the plurality of carton bottom panels. The pre-folding step can include rotating a pair of spindles each spindle having a pre-folding member into engagement with the carton bottom panels, and the final folding step can include rotating the pair of spindles, each spindle having a final folding member, into engagement with the carton bottom panels. The mandrel turret can be rotated about the fixed axis during the pre-folding and final folding steps.
Other features and advantages of the present invention will be apparent from the following detailed description, the accompanying drawings, and the appended claims.